Lead Extraction Sheath With Dynamic Gripping for Fibrotic Adherence
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Solution Overview
Problem
Challenging structural complexities and adherence issues in extracting cardiac pacing leads from precise locations within the heart, such as post-AV node locations, pose difficulties due to fibrotic tissue buildup, device malfunction, and infection risks, especially when attempting to remove affixed lead fragments.
Innovation Solution
An extraction device comprising an outer sheath and an inner member with a movable engagement portion that transitions between configurations to securely grasp and retract implanted leads, aided by a distal support member and optional accessories for stabilization and traction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional extraction methods are used to remove implanted leads, then the extraction process can be performed, but tissue avulsion and damage to surrounding structures may occur due to fibrotic tissue buildup and lead adherence
Solution Approach 1:
The extraction device is divided into multiple functional components: an outer sheath for stabilization, an inner member for engagement, and a distal support member for counter-traction. This segmentation allows each component to perform its specific function independently, reducing the risk of tissue damage during extraction.
Solution Approach 2:
The engagement portion of the inner member features a specialized geometry with tapered surfaces and gripping elements designed to locally concentrate force on the lead insulation rather than the surrounding tissue. This localized force application enables effective lead removal while protecting vulnerable cardiac structures from damage.
2Productivity
If force is applied to extract adhered lead fragments, then complete removal can be achieved, but risk of device malfunction or infection increases due to tissue damage
Solution Approach 1:
The device merges stabilization (outer sheath), engagement (inner member), and counter-traction (distal support member) functions into a single integrated system. This combination allows for controlled, gradual extraction of lead fragments without sudden force application that could cause tissue damage and subsequent infection.
Solution Approach 2:
The inner member acts as an intermediary between the operator and the implanted lead, providing a controlled interface for force application. The engagement portion's specific geometry mediates the interaction between extraction force and lead structure, enabling complete removal while minimizing tissue trauma and infection risk.
3Adaptability or versatility
If the extraction device is designed with complex engagement mechanisms to handle fibrotic tissue, then extraction capability is improved, but device complexity increases
Solution Approach 1:
The inner member is designed to be movable relative to the outer sheath, allowing dynamic adjustment of the engagement portion's position and configuration. This dynamic capability enables the device to adapt to various lead types and implantation sites while maintaining a relatively simple overall structure.
Solution Approach 2:
The inner member is nested within the outer sheath, and the engagement portion is integrated within the inner member structure. This nested configuration allows multiple functions to be contained within a compact form factor, reducing device complexity while maintaining extraction capability for challenging fibrotic tissue scenarios.
Data Source
AI summary
Extraction devices and methods of extracting an implanted medical device from a target location within a body lumen of an animal are provided. An extraction device comprises an outer sheath, an inner member disposed within, and axially movable relative to, the outer sheath, and a distal support member attached to the outer sheath and the inner member, the inner member comprising an engagement portion attached to the distal support member and movable between a first configuration having a first axial length and a first inner diameter and a second configuration having a second axial length that is greater than the first axial length and a second inner diameter that is less than the first inner diameter. A method of extracting an implanted medical device comprises inserting the distal end of an extraction device according to an embodiment into a body vessel of an animal; advancing the distal end of the extraction device to the target location and over the implanted medical device; engaging the implanted medical device with the engagement portion of the extraction device by retracting the inner member of the extraction device relative to the outer sheath of the extraction device, such as by application of a pulling force on the inner member of the extraction device while maintaining a position of the outer sheath of the extraction device; extracting the implanted medical device from tissue within which the medical device is implanted by retracting the extraction device within the body vessel; and withdrawing the extraction device and the implanted medical device from the body vessel.